线程、块与网格
GPU 执行模型
线程、块与网格 是 CoddyKit 上的免费 Mojo Academy 课时。 这是第 2 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Mojo Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Mojo Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
The Smallest Worker
A GPU runs your kernel as many tiny workers. Each single worker is a thread, and it usually handles one piece of data.
Grouping Threads
Threads are organized into a block. Threads in the same block can cooperate and share fast on-chip memory.
All Blocks Together
All the blocks for one kernel launch form the grid. The grid is the full set of workers handling your whole problem.
A Simple Hierarchy
The model nests neatly: threads live in blocks, and blocks live in a grid. Three levels describe every launch.
Each Thread Has an ID
Every thread can ask where it sits. Its index tells it which element of the data it is responsible for.
var tid = thread_idx.xEach Block Has an ID Too
Blocks are numbered as well. A thread combines its block id with its local id to find a unique spot.
var bid = block_idx.xComputing a Global Index
The classic formula maps each thread to one global element. This global index is how kernels split an array.
var i = block_idx.x * block_dim.x + thread_idx.xChoosing Block Size
You pick how many threads sit in a block. A good size keeps the hardware busy without wasting resources.
Choosing Grid Size
The grid must cover all your data. You size it so threads times blocks reach every element you need.
var blocks = (n + 255) // 256Guarding the Edges
The grid often launches a few extra threads. A simple bounds check stops them from touching memory past the end.
if i < n:
out[i] = a[i] + b[i]Why This Shape Helps
Blocks let groups share memory and sync, while the grid scales to any size. The structure maps work onto hardware cleanly.
Quick Check
A thread needs the position of its element across the whole array.
Recap
Threads group into blocks, blocks form the grid, and combining their ids gives each worker a unique global index. 🧵
常见问题解答
「线程、块与网格」课时是免费的吗？
是的 — 「线程、块与网格」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Mojo Academy 课程的其余内容，请升级到 CoddyKit PRO。 Mojo Academy 课程共包含 4 节课。
「线程、块与网格」这节课中我会学到什么？
GPU 执行模型 你通过在浏览器中直接运行的动手代码来练习 Mojo Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Mojo Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Mojo Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 2 节课，共 4 节。
「线程、块与网格」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Mojo Academy 课中编写并运行代码吗？
能。每节 Mojo Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。